VS 2010 Garbage Collection?
Jul 23, 2010
I thought that when a variable went out of scope (like a variable declared within a method - when you exit that method the variable is out of scope) then it was eligible for garbage collection and when it was garage collected the Dispose method is called on it. Now I know that it does not get disposed immediately but I assumed it would be basically as soon as the process starts to take up quite a bit of memory.However, I found that my app's memory usage seems to constantly increase when I dont manually Dispose of a specific method local variable. Of course its good practice to call Dispose and ordinarily I would but I just didn't realise that this particular class actually implemented IDisposable. The class in question was the System.DirectoryServices.SearchResultCollection class, and I was looping through the items in it like so:
[Code]...
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Oct 5, 2010
I have a callback function in a C+ dll:
<UnmanagedFunctionPointer(CallingConvention.Cdecl)> _
Public Delegate Sub DeviceDetectionEvent(ByVal YasdiEvent As YASDIDetectionSub, ByVal DeviceHandle As UInteger, ByVal param1 As UInteger)
[code].....
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Jan 11, 2011
I'm creating a windows forms program and have recently noticed a large amount of memory slowly being eaten by the application. I went through my program and tried to tie up as many loose ends as I could in relation to object creation but noticed that the program would still keep memory for every form loaded until it eventually crashed.
I decided to make a simple test program which sole purpose is to pop-up a new form with a few controls, wait for 200 milliseconds, then close the form and repeat the process 30 times every time I hit a button. I found it caused the same behavior, even with the only new object creation being that of the form. So, I decided to manually invoke the garbage collector in a subroutine which handles the formclosed event. During tests I would get some memory back occasionally, but not enough to make a difference in the long run. So I start setting the form variable to nothing before I called GC.collect(). The program will initially eat a few 1000K of memory before leveling off and using only 20-40K for every 30 forms created.
Now what I'm wondering is, what is the point of an automated garbage collection system if it requires constant manual evocation and explicit dereferencing of all new objects to be effective? Have I completely lost grasp on the scope of VB.Net forms and it simply never marks forms as available memory to be cleared?I would have thought object memory references created within a form would be marked as usable when the form's close or dispose routine is called and no references to objects created within the form exist anywhere outside the closed form.
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Sep 22, 2009
I am trying to create radiobuttons, and then create code for them after they are created. I have the code to create the radiobuttons. What I want to do is create a sub for the event of changing the check value for the radiobutton. Or to have the check value recognized by a button click. For example, you click the button and if the first radiobutton has the circle filled then a msgbox comes up and says hurray. My code so far is this:
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Nov 2, 2010
I am using a function from a dll in unmanaged code that requires a callback to my managed code in Visual Basic 2010. The callback is asynchronous and is called continuously over the life of the application. What's the best way to protect the callback function from the garbage collector? Right now it is being collected after several dozen calls from the dll.
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Feb 21, 2012
I've been doing some reading on garbage collection in .NET and I was hoping for some clarification. So, as I understand it if I declare a public shared class variable, the GC will never get rid of it. Is this correct?Also, what then of private variables? Take the following example:
public class myClass
private shared myString As String
public sub ChangeString(newString As String)
[code].....
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Jan 29, 2009
Is the memory from primitive data types (int, char,etc) immediately released once they leave scope, or added to garbage collection for later release?
consider:
For x as integer=0 to 1000
dim y as integer
Next
If this doesn't add 1000 integers to the garbage collector for clean up later,how does it treat string objects? would this create 1000 strings to clean up later?
For x as integer=0 to 1000
dim y as string=""
Next
How about structures that contain only int,string,etc... data types?
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Oct 6, 2009
Datatable object within class function + garbage collection?
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Feb 8, 2011
Here's the scenario, winforms application, monitoring via Task Manager Processes Tab.On initial launch spins up to ~61,000K (initial data grid and data loads)If I minimize the application, not touching or doing anything the Mem usage drops to 1,380K.When I restore the application is spins back up to only 5.8K
So my question is, does the minimize send some internal message to clean up resources since the application in question is not in focus?The first app I noticed this in happens to be VB.NET, but I've observed the same behavior in my main C# winform applications.
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Jan 23, 2009
If I use a single variable of type Excel.Worksheet to reference Worksheet1, and then change it to Worksheet2, Worksheet3 and so on, is it adequate to simply do "Marshal.FinalReleaseComObject(worksheetVariable)" once at the end? Or would I be left with some references still in memory? In other words, do I need to do a "Marshal.FinalReleaseComObject" before each re-assignment?
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Feb 3, 2010
I have a theory that the CLR garbage collection mechanism means that I can get away with circular references in my object hierarchy without creating deadlocks for teardown and garbage collection. Is this a safe assumption to make? (Target language VB.NET)
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Jul 30, 2009
Dim x as whatever
Try
x = new whatever(1)
something is done with x
[code]....
What happens to x = whatever(1)Does garbage collection find the pointer to the first new and destroy it or what?
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Mar 9, 2012
I've heard that the c# garbage collector can be 'more aggressive' than it's vb.net counterpart. Is this true? Are there any other differences in how garbage collection is run in vb.net vs. c#?
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Jun 15, 2009
I'm trying to introduce delay to my code so that it would read in the noise or garbage data.
I'm receiving the data from RFID to pic thru RS232.Is there any simple delay that i can use? I seriously don't understand threading.
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Dec 4, 2010
I have a function like the following: Public Function testFunction(ByVal input_string As String) As String
[Code]...
or just let the garbage collector do the job for us? Both the above functions work, but I want only know the best practice for performance...
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Mar 2, 2010
I'm using following code to receive content of a ListBox
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Jun 6, 2012
I am using vb.net 3.5 and application is interacting with VC++ dll.
code is:
Public Delegate Sub delProcess() //Globaly declare
im del As New delProcess(AddressOf Process) //Process is function which not returning
[code].....
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Sep 28, 2009
If I want to narrow scope of a variable in C#, I can introduce additional braces - i.e.:
class Program
{
static void Main(string[] args)[code].....
In the ide, I can no longer reference y outside of the scope introduced by the new braces. I would have thought that this would mean that the variable y would be available for garbage collection.(it is interesting to note that when viewing the compiled code using reflector it appears that there is no difference with or without the additional braces)Is there any way similar to this to narrow scope when using VB.net? Does this have any impact on when variables defined in the inner scope may be garbage collected?
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Oct 25, 2010
with VB.NET + MySQL i am having a connection object which is public public MYcnn as MySql.Data.MySqlClient.MySqlConnection when my main form opens MYcnn will open & will be available for all the procedures & functions. i never close this connection until the last form of the application closes (yes of course i compromise of some security + performance issues)
my problems is(1)when & how the garbage collector works to collect my connection object if my connection object remains open for > then certain time(2) how to offer or fix the time of my connection object availableness to garbage collector (3) i would like to write an event for the connection object closed event(i am explicitly declaring the connection object)
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Nov 26, 2010
I have an Excel file that downloads automatically, but for some reason the binary XLS file contains some garbage HTML text at the end of it.
When opening the file in the Excel application, it shows a warning but proceeding will automatically remove the garbage HTML text.
However, I need to open the file programmatically. When doing so via
Dim wb As Workbook = Excel.Workbooks.Open(ExcelFileName)
It throws:
Exception from HRESULT: 0x800A03EC
a) Get Excel to perform a similar action as if I manually opened it and remove the garbage HTML automatically. NOTE: Tried setting the XlCorruptLoad.xlRepairFile parameter and it didn't work.
OR
b) Remove the garbage text from the XLS binary file (FileStream?) and resave it before attempting to open the file with the code mentioned above.
The garbage html always comes at the very end of the file and starts with
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Sep 28, 2010
I converted a project from 2008 to 2010 to be able to use the TPL.I've updated the compile target to .NET 4. Everything seems good, including the .NET 4 specific TPL stuff...except that:[code]
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Aug 30, 2010
I'm trying to loop through a collection object in vb2010.The code was originally used in Vb6 The book said that I needed to code a NewEnumerator method first in order to be able to loop through my collection. I coded the following:
[code]...
It gives an error for IUnknown, staging that IUnknown is not accessible in this context because it is a 'Friend'.In the line in the function I removed the Set since it's no longer needed.The error message for this line is '_NewEnum' is not a member of 'Microsoft.VisualBasic.Collection'What are these messages and how do I fix this in VB 2010?m_colCourse is not a system collection.
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Apr 16, 2011
Ok say I have this Dim MyQueueOfClients as new Queue (Of TcpClient) I also have two threads.
In thread one a TcpListener waits for connections then adds a connected TcpClient to MyQueueOfClients.
MyQueueOfClients.Enqueue (TcpClient)In thread two I then check to see if there are any Clients in MyQueueOfClients. If so I then remove them from the MyQueueOfClients.
MyTcpClient = MyQueueOfClients.Dequeue I think the question Im asking is this thread safe?
Can I Enqueue and Dequeue at the same time from different threads?
Well it helps if you read everything. I have just read this as well
A Queue(Of T) can support multiple readers concurrently, as long as the collection is not modified. Even so, enumerating through a collection is intrinsically not a thread-safe procedure. To guarantee thread safety during enumeration, you can lock the collection during the entire enumeration. To allow the collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization.
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Jun 15, 2012
I am trying to work out a way to group a collection of items like an enum so that I can access them through code else where in my program. i.e I have list of items and sub items
[Code]...
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May 17, 2011
So one of my programs logged an error the other day that I am trying to fix. The error was Collection was modified; enumeration operation may not execute.To overly simplify my code, users can add or delete objects from the collection at runtime. In the background, on a separate thread, a process runs every so many seconds that syncs the data in the collection with the data in a flat file.
To avoid my problem, it seems the most logical to create a COPY of the collection at the start of my second thread's procedure, and run off of that.How do I do that?If I try to say something like.
[Code]...
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Apr 4, 2011
As the title says can I create a memorystream then use it in a FIFO manner like a Queue.When you use memorystream.write it writes data at the memorystream.postion.If I then want to read the beginning of the memory stream I have to set position to the beginning and do a memorystream.read.
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May 1, 2012
I have a problem with an application, in this case I have a windows services. its function is generate reports depending of demand of our users.In some cases the memory usage of my windows services is to 2 gb of RAM. I disposed all objects that my application use . but the memory usage doesn't low.I tried to reduce the memory usage forcing to garbage collector to Collect with the method "GC.Collect"but it's not recommend because uses many time of CPU.Surfing on the internet I found a method named "SetProcessWorkingSetSize" that free memory usage correctly. http:[url]....but some cases my windows services named sapdkadm_procesoestandarejecucion.exe has some error message in event viewer is the next:
Faulting application sapdkadm_procesoestandarejecucion.exe, version 1.0.0.0, stamp 4f908fef, faulting module kernel32.dll, version 5.2.3790.4480, stamp 49c51cdd, debug? 0, fault address 0x0000000000027ded.
The real problem is that when this happens my windows services restart
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Jul 12, 2011
I'm trying to query a DataTable to get a collection of rows but I'm finding that my search string has to be the exact length of the columns width. So, for example this won't work:
Dim rows As DataRow() = (From r In myTable.AsEnumerable() Where r.Field(Of String)("fname") = "Bob").ToArray()
...but this will:
Dim rows As DataRow() = (From r In myTable.AsEnumerable() Where r.Field(Of String)("fname") = "Bob ").ToArray()
The search term ("Bob") has to be padded with spaces to make it equal in length to the column width (10 characters). Is this how it's supposed to work or am I doing something wrong?Also, how can I do a LIKE search? So for example, I want to search for all names that start with "Bo" or whatever. ie. "Bo*".
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Oct 12, 2011
I have a problem that can be best solved with LINQ. I have a class that has 2 properties of which 1 is a single. I have a collection of that class and I need to select the instance with the highest single value.[code]I'm having a hard time explaining this even this is a simple task. Please ask if you don't understand.In addition to my original question, How would I create a collection containing the 5 highest Instances.
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May 22, 2010
I want to create some type of list or collection. Each item on this list or collection will need contain A string name and a integer value. Something like
[Code]...
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